A communication system that adopts OpenFlow has been known. A communication system using OpenFlow includes an OpenFlow switch and an OpenFlow controller as packet processing apparatuses.
An OpenFlow switch includes a flow table. A flow table defines a processing method for an input packet. When a packet is input to an OpenFlow switch, the packet is processed according to the definition in the flow table. Processing of the packet includes forwarding or discarding, for example.
In contrast, if a packet not defined in the flow table is input to the OpenFlow switch, the OpenFlow switch inquires the processing method for the packet from the OpenFlow controller. Upon receiving the processing method transmitted from the OpenFlow controller, the OpenFlow switch processes the packet based on the received processing method. A related-art technical document is “OpenFlow Switch Specification Version 1.0.0 (Wire Protocol 0x01)”, Dec. 31, 2009